Oats are available in variety of forms that can be used in formulation of different cereal based consumer products. Unlike other major grains, oats are seldom used as flour. This is due to the high lipid content, which makes oat flour highly adhesive and difficult to handle. Instead, most common wholegrain oat product is oat flakes, which are often used as a raw material in oat baking. Oat flakes, or oat rolls, are prepared form oat groat after the unpalatable hull has been removed.
Flakes are available in different thicknesses that retain their structure differently during baking process and that require different cooking time. Prior the flaking, oat grains can be cut into three to four pieces to yield steel cut grains. These groat parts are sometimes used as such in baking processes without further grinding or flaking.
Oat flour or oat meal is produced by grinding flakes or groats into flour for use as an ingredient in a wide variety of food products. Typically oat starch is partly gelatinized or damaged to overcome problems with product handling.
Oat bran is a dietary fibre and beta-glucan enriched oat fraction that can be used in products aiming towards improved nutritional status. Oat bran is usually separated from endosperm components by sieving or classification processes. Traditional oat bran products have beta-glucan content around 8 to 12 %, whereas oat bran concentrates can have remarkably higher beta-glucan content (see attached table). For AACC definition of oat bran please see: http://www.aaccnet.org/definitions/oatbran.asp.
Different bran ingredients are typically available as coarse or fine flour, or as an extrudate with slightly roasted flavour. Concurrently with the production of beta-glucan fraction, an endosperm fraction is recovered as a co-product. This endosperm fraction has a lower dietary fibre and beta-glucan contents than the wholegrain oat products. Such flour can be used in applications where dietary fibre content is not striven.Several special oat fractions are also available for specific usage. Oat oil consists of polar and non-polar fractions. Non-polar oat lipids are comparable to other vegetable oils and it has a nutritionally favourable fatty acids composition and is rich in lipid soluble antioxidant. Polar lipid fraction has a large potential to be used as emulsifier agent and has potential applications also beyond food products.
Two other emerging oat ingredients have recently gained lot of interest:
1) Various oat extracts are available for both food and cosmetic applications. In food applications these are used to provide oat flavour and health benefits without technical limitations evident for other oat products.
2) Due to the fact that many celiac patients have recognised oat as a suitable cereal source there is increasing demand for oat protein concentrates with tailored technological properties.
Guan, X., Yao, H., Chen, Z., Shan, L., Zhang, M. (2006). Some functional properties of oat bran protein concentrate modified by trypsin, Food Chem 101, pp. 163-170.
Wu, Y.V., Doehlert, D.C. (2002). Enrichment of β-glucan in oat bran by fine grinding and air classification. LWT - Food Sci Technol 35, pp. 30-33.
Peterson, D.M. (2002). Oat lipids: composition, separation and applications. Lipid Technology 14, pp. 56-59.
Erazo-Castrejon, S. V., Doehlert, D. C., D'Appolonia, B. L. (2001). Application of oat oil in breadbaking. Cereal Chem 78, pp. 243-248.
Peterson, D.M., Wood, D. F. (1997). Composition and structure of high-oil oat. J Cereal Sci 26, pp. 121-128.